From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e8.ny.us.ibm.com (e8.ny.us.ibm.com [32.97.182.138]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id F1F011A0BD3 for ; Thu, 29 Jan 2015 13:16:26 +1100 (AEDT) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 28 Jan 2015 21:16:24 -0500 Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 685AB6E803F for ; Wed, 28 Jan 2015 21:08:14 -0500 (EST) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0T2GLA226476604 for ; Thu, 29 Jan 2015 02:16:21 GMT Received: from d01av02.pok.ibm.com (localhost [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0T2GJRu003196 for ; Wed, 28 Jan 2015 21:16:20 -0500 From: Ryan Grimm To: imunsie@au1.ibm.com, mikey@neuling.org Subject: [PATCH] CXL: Fix device_node reference counting Date: Wed, 28 Jan 2015 20:16:04 -0600 Message-Id: <1422497764-24582-1-git-send-email-grimm@linux.vnet.ibm.com> Cc: Ryan Grimm , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When unbinding and rebinding the driver on a system with a card in PHB0, this error condition is reached after a few attempts: ERROR: Bad of_node_put() on /pciex@3fffe40000000 CPU: 0 PID: 3040 Comm: bash Not tainted 3.18.0-rc3-12545-g3627ffe #152 Call Trace: [c000000721acb5c0] [c00000000086ef94] .dump_stack+0x84/0xb0 (unreliable) [c000000721acb640] [c00000000073a0a8] .of_node_release+0xd8/0xe0 [c000000721acb6d0] [c00000000044bc44] .kobject_release+0x74/0xe0 [c000000721acb760] [c0000000007394fc] .of_node_put+0x1c/0x30 [c000000721acb7d0] [c000000000545cd8] .cxl_probe+0x1a98/0x1d50 [c000000721acb900] [c0000000004845a0] .local_pci_probe+0x40/0xc0 [c000000721acb980] [c000000000484998] .pci_device_probe+0x128/0x170 [c000000721acba30] [c00000000052400c] .driver_probe_device+0xac/0x2a0 [c000000721acbad0] [c000000000522468] .bind_store+0x108/0x160 [c000000721acbb70] [c000000000521448] .drv_attr_store+0x38/0x60 [c000000721acbbe0] [c000000000293840] .sysfs_kf_write+0x60/0xa0 [c000000721acbc50] [c000000000292500] .kernfs_fop_write+0x140/0x1d0 [c000000721acbcf0] [c000000000208648] .vfs_write+0xd8/0x260 [c000000721acbd90] [c000000000208b18] .SyS_write+0x58/0x100 [c000000721acbe30] [c000000000009258] syscall_exit+0x0/0x98 We are missing a call to of_node_get. pnv_pci_to_phb_node should call of_node_get otherwise np's reference count isn't incremented and it might go away. Rename pnv_pci_to_phb_node to pnv_pci_get_phb_node so it's clear it calls of_node_get. Signed-off-by: Ryan Grimm --- Please consider this patch for stable. Without this fix, node reference counting is broken. arch/powerpc/include/asm/pnv-pci.h | 2 +- arch/powerpc/platforms/powernv/pci-ioda.c | 6 +++--- drivers/misc/cxl/pci.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/pnv-pci.h b/arch/powerpc/include/asm/pnv-pci.h index 3c00d64..f9b4982 100644 --- a/arch/powerpc/include/asm/pnv-pci.h +++ b/arch/powerpc/include/asm/pnv-pci.h @@ -19,7 +19,7 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq, int pnv_cxl_alloc_hwirqs(struct pci_dev *dev, int num); void pnv_cxl_release_hwirqs(struct pci_dev *dev, int hwirq, int num); int pnv_cxl_get_irq_count(struct pci_dev *dev); -struct device_node *pnv_pci_to_phb_node(struct pci_dev *dev); +struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev); #ifdef CONFIG_CXL_BASE int pnv_cxl_alloc_hwirq_ranges(struct cxl_irq_ranges *irqs, diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 5d52d6f..8be1d4f 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -1460,13 +1460,13 @@ static void set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq) #ifdef CONFIG_CXL_BASE -struct device_node *pnv_pci_to_phb_node(struct pci_dev *dev) +struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev) { struct pci_controller *hose = pci_bus_to_host(dev->bus); - return hose->dn; + return of_node_get(hose->dn); } -EXPORT_SYMBOL(pnv_pci_to_phb_node); +EXPORT_SYMBOL(pnv_pci_get_phb_node); int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode) { diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index 428ea8ba..cb25067 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -317,7 +317,7 @@ static int init_implementation_adapter_regs(struct cxl *adapter, struct pci_dev u64 psl_dsnctl; u64 chipid; - if (!(np = pnv_pci_to_phb_node(dev))) + if (!(np = pnv_pci_get_phb_node(dev))) return -ENODEV; while (np && !(prop = of_get_property(np, "ibm,chip-id", NULL))) -- 1.9.1